Thai soldiers move in to pro-government demonstration site after the coup, May 22, on the outskirts of Bangkok, Thailand. Thailand's new military junta has announced that it has suspended the country's constitution.

Wason Wanichakorn/AP

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This story was updated at 15:00 with the latest developments.

No shots were fired on Tuesday when the Thai military imposed martial law, insisting that this was not a coup.

Sure, armored personnel carriers rolled out into the streets, the army shut down partisan media outlets, and the prime minister was cut out of the loop, but Thai Army Chief Prayuth Chan-ocha at first insisted this was no coup.

Well, today the pretense was emphatically dropped, with Gen. Prayuth announcing that he was taking charge of Thailand. For years, the country has been roiled by political turmoil that broadly pits elites and the urban middle class against rural and poorer Thais who repeatedly vote for leaders deemed unpalatable by traditional elites.

An interim cabinet now answers to the military, TV news broadcasts have been cut, and political meetings and protests have been banned. Prayuth presented the coup as a necessary step in his televised address Thursday.

"In order for the situation to return to normal quickly and for society to love and be at peace again ... and to reform the political, economic and social structure, the military needs to take control of power," he said, according to a translation by Reuters.

US Secretary of State responded in a sharply-worded statement that referred to his "disappointment" and said that "this act will have negative implications for the U.S.–Thai relationship, especially for our relationship with the Thai military." He continued:

I am concerned by reports that senior political leaders of Thailand’s major parties have been detained and call for their release. I am also concerned that media outlets have been shut down. I urge the restoration of civilian government immediately, a return to democracy, and respect for human rights and fundamental freedoms, such as press freedoms. The path forward for Thailand must include early elections that reflect the will of the people.

In addition to shutting down local TV news stations, Thailand appeared to be jamming broadcasts of international news outlets like the BBC and CNN. A BBC producer tweeted that the channel's signal is now being overridden by Thai state programming, including a logo for the junta now in charge, which is calling itself the National and Peace and Order Maintaining Council.

Bangkok's The Nation newspaper reports, citing an unnamed source, that Prayuth leaned on both pro and anti-government politicians at a meeting on Wednesday to resolve their differences, something they failed to do. Prayuth then broke up the meeting and reconvened it later. He asked interim Justice Minister Chaikasem Nitisiri if the government would resign. Chaikasem refused and Prayuth responded, according to the paper: "Then as of this minute, I have decided to seize power." All of the attendees at the meeting have since been taken into custody.

What comes next could be bloody confrontation, not peace. Thailand's so-called "red shirts," supporters of Thaksin Shinawatra, who was deposed as prime minister by a coup in 2006, and his sister Yingluck Shinawatra, who was deposed by a court order earlier this month, are likely to be made even angrier by this move. The military has already begun roughly dismantling a red shirt encampment in Bangkok, while also dispersing followers of anti-Shinwatra firebrand Suthep Thaugsuban.

Mr. Suthep led months of protests against Ms. Yingluck's premiership, and opposed plans announced on May 1 for July elections as a possible exit from the crisis. The reason is simple: Yingluck was tipped to win at the polls. Instead Suthep, a veteran opposition politician, called for an appointed government whose members he and his allies would select to run the country for an unspecified period of time.

The gap between these two factions remains as wide as ever, and whether the military will be able to cajole a political compromise now, something it failed to accomplish after its 2006 coup, is uncertain at best.

The Thai coup is forcing the US to confront an uncomfortable reality with parallels to Egypt, where the military staged a coup last July. As with Egypt, the US has close military ties with Thailand. Many Thai officers attending US military training courses, and the two militaries share intelligence on counterterrorism and stage annual multinational war games called "Cobra Gold." This year's Cobra Gold in February involved almost 4,000 US troops and around 9,000 soldiers from Thailand, Singapore, Indonesia, South Korea, Japan and Malaysia.

The US Leahy Amendment bans the US military from doing business with foreign militaries that engage in coups. The Obama administration has finessed this in the case of Egypt and is likely to do so in the case of Thailand, as foreshadowed by its reaction to the declaration of martial law in Thailand.

State Department Spokesperson Jen Psaki said in a statement after that declaration (emphasis mine):

We are aware of reports that Thailand’s army has declared martial law and are monitoring developments closely. We remain very concerned about the deepening political crisis in Thailand and urge all parties to respect democratic principles, including respect for freedom of speech. We understand the Royal Thai Army announced that this martial law declaration is not a coup. We expect the Army to honor its commitment to make this a temporary action to prevent violence, and to not undermine democratic institutions. The United States firmly believes all parties must work together to resolve differences through dialogue and find a way forward. This development underscores the need for elections to determine the will of the Thai people.

Thai democratic institutions, such as they are, were undermined by the 2006 coup, the court-ordered removal of Yingluck, and the declaration of martial law on Sunday. They have been further undermined by the military's actions today. Secretary Kerry acknowledged that in his statement, saying: "We are reviewing our military and other assistance and engagements, consistent with U.S. law."

US training of foreign military officers is often claimed to be a means to make their military more receptive to democracy and subordination to elected civilians, though is hasn't always worked in practice. The US says its International Military Education and Training Program (IMET) "facilitates the development of important professional and personal relationships, which have proven to provide U.S. access and influence in a critical sector of society that often plays a pivotal role in supporting, or transitioning to, democratic governments."

If US officials are to be believed, they were blindsided by the Thai military's swift action. Amy Searight, the US Department of Defense's director for East Asia, told a conference in Washington at the end of last week that the US was "reasonably confident" that the military would not carry out a coup.

That confidence was clearly misplaced.

Coups are nothing unusual in Thailand. The country has witnessed 21 coups, attempted and successful, since 1912, and nine since 1971 (that's a coup every 4.8 years).

However, they have not been as damaging to the prosperity of the nation as one would expect. The nine coups since 1971 may have acted as a drag on economic progress, but the country's gains have still been remarkable. Thai GDP growth has averaged 7.7 percent a year between 1970 and 2012, and key indicators of well-being have also soared. Life expectancy at birth was 62 in 1970. It is now at about 77 years.

To be sure, there are signs that the political impasse of the past seven years is finally taking a toll. GDP contracted 0.6 percent in the first quarter of this year, compared to the same quarter in 2013, and there's little reason for economic optimism in the short term.

Beyond that, it's now up to Thailand's generals, and perhaps the still widely-respected monarchy, to forge some kind of workable compromise.